Yes, openSUSE can be used as dom0. Currently I have two Xen hosts in an active/passive cluster running on openSUSE 11.4. I used Xen from the repositories. Seems to work quite well. openVSwitch takes care of (VLAN) networking for the domUs.

-- "There has grown up in the minds of certain groups in this country the notion that because a man or corporation has made a profit out of the public for a number of years, the government and the courts are charged with the duty of guaranteeing such profit in the future, even in the face of changing circumstances and contrary to public interest. This strange doctrine is not supported by statute nor common law."